wefalck
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Everything posted by wefalck
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Are you going to skim over the horizontal flats in situ - this seems to have been the practice on all the chucks I have for my lathes, judging by the shape of the edges of the jaws. This ensures that the flats run perpendicular to the axis of the lathe. -
You didn't have an 1/16" end-mill ? That would have been another option for milling the slots into the jaws. Or to make a low-profile saw-holder that uses an internal thread and a screw to clamp the saw. Putting a plate in front of the chuck-body is avoiding to have to use a T-slot cutter, but from an engineering point of view is a weaker design than a solid body.
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Indeed, and I would not use it on thick stock, where lots of material is to be removed. However, I am using sometimes the 20 to 40 mm diameter versions on the saw table of my lathe for thin stuff. Make sure you get a cutting-saw, that is one where the coating is on the rim and extends some mm on the side surfaces. Disks that are covered all over in diamond are for grinding and may get stuck, as there is no clearance when you feed them in further.
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I think Underhill's book has a sketch for this arrangement, but I may be mistaken, as such detail drawings are a bit dispersed around the book. Basically, the eyesplice of the block is fed through the cringle and then turned over it - a simple, straightforward operation, but difficult to describe ...
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Internally stropped blocks are mechanically a better solution, because the iron strop support the axle closer to the sheave. However, I think, they only became practical, when rolled iron bars became available in larger quantities from around the second quarter of the 19th century on. Calibrated iron bar allows to mass-produce the block-shells on machines, as the slot for bar can be milled to a given dimension, rather than being fitted to each strop. Internally stropped blocks would be found in locations, where heavier strain is expected and where there is no risk that they would chafe sails. In locations where the latter may be a risk, rope-stropped blocks were preferred for a long time. Underhill's book on rigging would be an appropriate source for the 1860s details.
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On the Internet you can find all sorts of sizes and grades of diamond-coated cutting saws. They are not only used in tile etc. cutting, but also for cutting gem-stones.
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She looks elegant in her frames 👍
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As these protrusion serve to preven the eyes of the topping-lifts from slipping inward, they should be 90° off-set compared to the direction of pull of these.
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I wholeheartedly agree that for an iron or steel ship metal (brass, copper) or some hard plastic (bakelite paper) is the material to go for. It best represents the metal surfaces. I found that thin sheet metal can sawed more easily with the saw-blade in reverse, at least for fretsaws. I haven't tried this with circular saws. In this way there is less a tendency to hook do to uneven manual feed. Nice metalwork on forecastle, btw. !
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My material of choice is a fast-drying solvent-based varnish that is sold over here in Europe as zapon-lacquer. In composition it is rather similar to solvent-based nail-varnish. Apart being fast-drying, i.e. within minutes, it has the advantage that you can undo any knots with a drop of solvent (acetone) should the need arise.
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One possibility to duplicate parts, such as the shell is to use a shaped turning bit. This can be ground from a piece of old hacksaw-blade. You would need a bit of a clearing angle, but no top-rake for brass. One would rough out the shape with normal turning tools and just give the part the final shape with the shaped bit. Coming on nicely, the model !
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Screw it well down, the base for the 3-pounder-QF - according to the video, when they first tried it out, it flew off the boat taking the crew with it ...
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Small bench-lathes typically had an external spindle cone in front of the spindle thread. The chucks or the back-plates then had a matching internal cone. I think your spindle nose is too short to add this feature in retrospect. When used with collets, the spindle-thread was usually covered with a brass ferrule as protection. Small watchmaking lathes only have internal spindle cones (as used for collets) and the chucks are mounted on arbors that have the same body as the collets (and are pulled in with a draw-tube). While this is too weak for heavy work, it gives the best concentricity for interchangeable chucks.
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I recently became aware of a YouTube-video that tells the story of the ships/boats on Lake Tanganjika: The images used are those that you showed in the first post. Any progress on the model?
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We shouldn't be too hard on the 'old masters', such as Boudriot or Marquardt, because they wrote their books at a time, when research was much more involved and difficult as it is often today. Today, we have a lot of resources at our fingertips, which they didn't have. Just a few days ago I edited a manuscript of Marquardt that will posthumously published in the German LOGBUCH and found several (small) errors through a quick Internet-search ... I suppose there is also a cultural difference between countries with respect how such details were treated. In general, the French seem to be much more prescriptive, while the Americans and Brits are more pragmatic and gave individual yards more lee-way. As probably no real practical examples survived, we have to rely on descriptions, textbooks and the likes, that describe how things should have been not how they have been in reality.
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You are absolutely right, that a threaded mount does not give concentricity, which is why there is usually some cone onto which a part is pulled with the thread. Or, on full-size lathes you mount an oversize 'back-plate', which then is turned to the exact size of a recess in the back of a chuck and which provides the register for it. However, this is not crucial for a 4-jaw-chuck, because you would set with the help of an indicator whatever feature (hole, boss, etc.) you want to run true. So, such chuck technically speaking does not need to run perfectly true. On the other hand it can be a bit irritating, when the body of the chuck does not run true ...
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The flag came out nicely indeed. If the glue is not too stiff, I would round out the sharp diagonal creases somewhat to give the flag a bit more volume. If there is no wind, the diagonal crease from the upper corner would hang down parallel to the flagg-staff, rather than sticking out at 45°. Conversely, if it sticks out at an angle, then because some wind is caught in it, billowing it out ...
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I agree that this is a very nice rendering of these straps ... but I don't like them as such, they look not very ship-shape, more like securing a load on a commercial lorry ...
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If Frankenstein made a bandsaw ...
wefalck replied to bruce d's topic in Modeling tools and Workshop Equipment
It's quite amazing what versatile machines were made in the past - now we have make do with simple, boring ones. OK, today we other methods to cut such compound curves. -
Richard, I think you were referring to the 'gallery' along the rails of Green Park at Piccadilly. I haven't been to London in summer for ages, but I think it still exists - we usually pop over from Paris for a pre-Christmas (shopping-)trip and to see friends, unless I have some business in the UK during the year. The last trip was atually just before the 'lock-down' in 2020 to visit the Model & Engineering Exhibition at Alexandra Palace - not quite the same anymore as it was in earlier decades. My colleagues in Nottingham (where I spent four years) used to say that the town-planners of the 1960s/70s did more damage to the British inner cities than the Luftwaffe. Radiating from the Docklands the whole of eastern London up to the old City changed its appearance, where there were still WW2 craters and no-go areas for tourists in the 1970s its all glass, concrete and steel now ... but we shouldn't dilute this building log with such nostalgic ranting 😉
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Thanks for your kind word about by engineering and photographic endeavours! I haven't gone back to Speakers' Corner in decades, but have the feeling that it is not as original as it was (or appeared to me/us) back in those days. I was there as a teenager and wish I had then the photographic experience and equipment I have now. A lot of picturesque aspects of London, such as the markets (Billingsgate, Covent Garden, Smithfield, etc.) have disappeared. I wish I had taken more pictures then (but film was expensive). Back in the 1970s and 1980s London's Clerkenwell Rd. (east of Farringdon) still was a paradise for precision engineering supply needs. I remember visiting the last watchmaking suppliers in around 1989 (Shorts Bros.), shortly before they threw the towel. And there were lots of model shops all over town, plus Model Boats down in Greenwich ...
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The CHARLES W. MORGAN should have had such structure, so perhaps contacting Mystic Seaport might help? On the other hand, the stoves/baking oven on ordinary warships must have been very busy at times and I don't recall having seen such structure under their bottoms in contemporary drawings. There would be some sort of iron drip-tray around them to prevent the surrounding deck from becoming soiled.
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I prefer ball-cranks over handwheels, but didn't actually make any myself, because I found a source for small ones. However, I made quite a few ball-handles. Here is my procedure for them (you have to scroll about half-way down the page): https://www.maritima-et-mechanika.org/tools/micromill/micromill.html. I should add, that I made myself a ball-turning attachment about 15 years ago, which greatly facilitates such operations. The worst are those turning sleeves on the handles of crank-wheels, no feel for fine machining ...
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